Wind turbine system for buildings

ABSTRACT

Systems and methods for capturing the energy of wind currents by placing wind-driven turbines in vortices formed near one or more edges of a building&#39;s roof, where the wind currents are concentrated by deflection of the wind off the horizontal faces of the building. In one embodiment, a cylindrical wind turbine is placed near the edge of a building&#39;s rooftop. The turbine structure drives an electrical generator. The axis of rotation of the turbine is parallel to the ground and to the edge of the building. A concentrator may be used to concentrate vortex winds into the turbine. Turbines can be installed on multiple sides of the building to optimize the system for variations in wind direction with changes in seasons or weather conditions.

RELATED APPLICATIONS

This application is related to of U.S. Pat. No. 7,315,093, issued Jan.1, 2008, which claims the benefit of U.S. Provisional Patent ApplicationSer. No. 60/763,615 by John F. Graham, filed Jan. 31, 2006, both ofwhich are hereby incorporated by reference as if set forth herein intheir entirety.

BACKGROUND

1. Field of the Invention

The invention relates generally to wind turbines, and more particularlyto systems and methods for harnessing energy from vortex winds createdby strong updraft winds flowing vertically along a building wall. Theturbine system includes deflectors and concentrators or augmenters tomaximize wind velocity for purpose of energy generation.

2. Related Art

Wind turbines of many types have been used to generate electricity in avariety of ways. The prior art describes turbines in a variety oflocations including natural ridgelines, open fields, mesas and on ships.Recent design concepts for rebuilding the World Trade Center showedplans to incorporate wind turbines in that structure to harness theelectrical generating power of passing winds.

These turbines for generating electricity take many forms including thefollowing.

Horizontal Axis Turbines (traditional-looking windmills) operate withfan-like rotors that look like airplane propellers that face into oraway from the wind. The Horizontal Axis Turbine is the most commonturbine configuration used today.

The Darrieus Turbine which looks roughly cylindrical, with wind-catchingblades that span the length of the cylinder often described as lookinglike an egg beater. This vertical axis turbine has vertical blades thatrotate into and out of the wind, the blades are placed roughly parallelin an arc to the axis. Guy cables are usually used to keep the turbineerect. In addition to keeping the turbine erect, the cables impose alarge thrust loading on the main turbine bearings, causing increasedwear on the bearings. With this type of turbine, replacing main bearingsrequires that the turbine be taken down. The Darrieus was invented inthe 1920's and is not widely used today.

The Darrieus Turbine is also related to machines with straight verticalaxis blades called Giromills or cycloturbines which use a wind vane tomechanically orient a blade pitch change mechanism. They were designedto be mounted on a tower or other device. The cycloturbine was marketedcommercially for several years, but never progressed beyond the researchstage.

The Savonius Turbine is S-shaped if viewed from above. The turbine turnsrelatively slowly, but yields high torque. It has been proven useful forpumping water and other tasks, but its slow rotational speeds have notbeen proven to generate electricity cost effectively from wind power.

The present types of turbines in commercial use are generally deployedin open fields or mesas, as far from wind-slowing obstructions aspossible to allow wind to strike their airfoils or blades at maximumspeed. They are raised above the ground as much as possible to bring theairfoils away from wind-slowing ground effects.

Augmenters deflectors and concentrators have also been developed to tryto concentrate wind onto the turbines, but they have not been proven tobe economically successful in commercial use.

SUMMARY OF THE INVENTION

This disclosure is directed to systems and methods for using windturbines that solve one or more of the problems discussed above. Oneembodiment comprises a system for capturing the energy of wind currentsby placing wind driven turbines at one or more edges of a building'sroof, where the wind currents are concentrated by deflection of the windoff the vertical faces of the building and further concentrated, into arotational vortex flow, with a series of deflectors and concentrators oraugmenters.

In one embodiment, a power-generating wind turbine structure withintegrated adjustable concentrators or deflectors is placed at (on ornear) the edge of a building's rooftop to harness updraft wind vortexcreated behind deflector. The device may employ a variety of differentturbine styles, including helical, hydro, straight-wing or cylindricaltypes (as will be described in more detail below,) propeller-style,squirrel cage or any other type. The axis of rotation is parallel to theground and parallel to the edge of the building. The placement of theturbine structure near the edge of the building allows it to use thebuilding wall as a passive concentrator to funnel wind up (updraft) theface of the building and into the turbine structure. A concentrator maybe used to help catch and direct updraft or rising winds into theturbine at the same time concentrating wind vortex rotating around thecenter of the axle. Turbines can be installed on multiple sides of thebuilding to optimize the system for variations in wind direction withchanges in seasons or weather conditions.

In one embodiment, the wind turbine has a cylindrical turbine structure,and the turbine is oriented with its axis parallel to the edge of theroof. The wind turbine may be positioned adjacent to a building edge, sothat the attached or standalone concentrator screens at least a portionof the negative wind flow from the turbine as the blades rotate. Adeflector may be attached to the parapet wall (if existing) or theturbine frame itself to redirect the concentrated wind flow toward adesired portion of the wind turbine to increase efficiency. In oneembodiment, the wind turbine is coupled with a system of pulleys to agenerator which generates electricity when driven by the wind turbine.The system may include a concentrator to redirect wind flow over theedge of the roof to a desired portion of the wind turbine. Theconcentrator may be adjustably positioned to enhance or spoil wind flowto the wind turbine. The system may also include solar cells mounted onthe concentrator and configured to generate electricity from sun lightcontacting them. The system may further include a deflector positionedon the side of the wind turbine opposite the edge of the roof toredirect wind flow originating opposite the edge of the roof to adesired portion of the wind turbine enabling the turbine to utilize thewind from multiple directions.

Yet another embodiment comprises a method including providing a windturbine, mounting the turbine on a roof of a building, and positioningthe turbine at the edge of the roof within wind flow which is passivelyconcentrated by the vertical face of the building and flows up and overthe edge of the roof. The method may further include concentrating orspoiling the flow of wind onto the wind turbine, driving a generatorwith the wind turbine to generate electricity, and coupling the windturbine to a set of solar cells to generate electricity in the absenceof wind, among other things.

Numerous other embodiments are also possible.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the invention may become apparent uponreading the following detailed description and upon reference to theaccompanying drawings.

FIG. 1 is a diagram illustrating rotational vortex wind flow nearbuilding edge created by updraft winds from vertical face of building.

FIG. 2 is a diagram illustrating the effect a deflector or existingparapet have on wind vortex created from building updraft winds.

FIG. 3 is a detailed diagram illustrating the placement of the windturbine system near the edge of the roof to take advantage of theconcentrated wind flow from updraft winds.

FIG. 4 is a diagram illustrating a reverse-wind-flow deflector as usedin one embodiment.

FIG. 5 is a diagram illustrating the air flow over a concave angleddeflector which is mounted in front of the turbine at the bottom.

FIG. 6 is a diagram illustrating the turbine system connected toexisting parapet wall.

FIG. 7 is a diagram illustrating a side mounted concentrator, placedbehind turbine directing air passing to the right or left of the turbineto the lower portion of the turbine blades, dragging them towards theedge of the building.

While the invention is subject to various modifications and alternativeforms, specific embodiments thereof are shown by way of example in thedrawings and the accompanying detailed description. It should beunderstood, however, that the drawings and detailed description are notintended to limit the invention to the particular embodiment which isdescribed. This disclosure is instead intended to cover allmodifications, equivalents and alternatives falling within the scope ofthe present invention as defined by the appended claims.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

One or more embodiments of the invention are described below. It shouldbe noted that these and any other embodiments described below areexemplary and are intended to be illustrative of the invention ratherthan limiting.

As described herein, various embodiments of the invention comprisesystems and methods for capturing the energy of wind currents by placingwind-driven turbines at one or more edges or the perimeter of abuilding's roof, where the wind currents are concentrated by deflectionof the wind off a series of wind deflectors, augmenters, concentratorsand the vertical faces of the building creating a vortex wind flow thatrotates in a circular motion around turbine axle.

In one embodiment, an energy generation system makes use of acylindrical turbine having multiple blades that are parallel to the axis(axis of rotation) of the turbine. The turbine is positioned on the roofof a building, near the edge of the roof on its perimeter. The turbineis oriented horizontally, with its axis parallel to the edge of theroof. In this embodiment, a deflector, attached to the turbine frame,extends upward from the edge of the roof. The turbine and the deflectormay adjust to make the axis of the turbine at roughly the same height asthe top of the deflector so that the updraft coming over the buildingedge and deflector hits the upper portion of the turbine and pushes theturbine blades away from the edge of the roof. The lower portion of theturbine is shielded from the vortex wind so that the wind (air eddies)does not push against the turbine blades as they rotate back toward theedge of the roof.

As the wind pushes the blades of the turbine, the blades rotate on ashaft that is on the axis of the turbine. In this embodiment, a pulley(or gear) is attached to the turbine shaft so that it rotates with theshaft. The pulley drives a belt or chain that in turn drives a generatoror alternator. The generator produces electrical current that can beused to power electrical circuits in the building and/or to rechargebatteries that can store the energy for later use. This embodiment alsoincludes a wind concentrator that redirects additional airflow into theturbine. The concentrator is adjustable and may employ solar cells togenerate additional electricity.

Referring to FIG. 1, a diagram illustrating wind flow over a building isshown. In this figure, the wind is blowing from the left side of thefigure to the right side of the figure. The wind vortex can be seenrotating in a circular motion. As the wind approaches building 110 anddeflector (120), it is deflected, since it cannot flow through thebuilding. The wind can only flow upward and over the building, or aroundthe building. FIG. 1 shows that the wind which is blocked by thebuilding turns upward. The wind which is not blocked by the buildingcontinues to flow essentially horizontally. This essentially funnels thewind through a relatively narrow space at the edge of the roof. Thiseffectively concentrates the wind currents into a vortex or circularrotational pattern which causes the wind speed to be higher at thispoint than at an open and unobstructed point on the ground or otherlocations upon rooftop.

It should also be noted that the wind creates a vortex or circularmotion at a certain distance from the building edge and or deflectordepending on its height. The higher the deflector, the further thecircular motion would be from the wall. Then the wind can begin to flownaturally horizontally again. This effect is shown in FIG. 2. Thepositioning of the turbine structure may be positioned to take advantageof the circular motion of the wind caused by updraft (upward flow ofwind against building) in addition to complementary system of deflectorsand concentrators.

Referring to FIG. 2, a diagram illustrating the positioning of the windturbine at the at the center of the updraft vortex taking advantage ofthe concentrated wind flow at this point is shown. Again, the wind isshown flowing from the left side of the figure to the right side of thefigure, where it is deflected by building 210, causing it to beconcentrated at the edge 221 of the roof 220. Wind turbine structure 230is placed at the edge of the roof, where the concentrated wind flow candrive the turbine.

In this embodiment, wind turbine 230 has a cylindrical structure. (FIG.2 shows the end of wind turbine 230—the length of the wind turbineextends into the page.) The axis of wind turbine 230 (around which theturbine blades are driven by the wind) is parallel to edge 221 of roof220. As indicated in figure, the blades of wind turbine 230 are drivenin a clockwise direction by the flow of the wind, which in thisembodiment is stronger across the top of the turbine structure. Thelength of the cylindrical structure of wind turbine 230 will typicallybe determined by practical design considerations, but one or moreturbines may extend along the edge of the roof. To cut back on equipmentand maintenance costs the turbines may be mechanically coupled to eachother, or they may operate independently. Connected turbines may operateat different speeds using a flexible drive shaft coupling.

Referring to FIG. 3, a more detailed diagram illustrating the structureof a wind turbine system in accordance with one embodiment is shown. Inthis figure, wind turbine structure 330 is positioned at the edge ofroof 320 of building 310. It should be noted that references to the“edge” of the roof should be broadly construed to include positionswhich are not only at the junction of the horizontal roof 320 andvertical face 315 of building 310, but also positions which aresufficiently close to this junction to place the blades or paddles ofthe turbine structure at least partially within the concentrated updraftvortex (wind flow which comes over the edge of the building).

In this embodiment, wind turbine structure 330 includes a turbineportion 335 and a support structure 336. As depicted in the FIG. 3,turbine portion 335 has a cylindrical structure including a set ofblades (e.g. 331) which are supported by arms (e.g. 332) that areconnected to a central hub 333. Hub 333 rotates around an axle at theaxis of the cylindrical structure, thereby allowing the turbine bladesto rotate around this axis as well. The axle is held by supportstructure 336 which, in this embodiment, consists of a simple frame.Support structure 336 maintains the positioning of turbine portion 335with respect to the up draft vortex or wind flow over the edge of thebuilding (as indicated by the arrows.)

It should be noted that in one embodiment, turbine portion 335 includestwo sets of blades that are offset from each other, both along the axisof the turbine and angularly. For instance, referring to FIG. 3. oneembodiment employs a turbine portion 335 which is eight feet long (intothe page in the figure.) A first set of three blades and supporting arms(e.g., 331 and 332) are shown using solid lines. Each of these blades isfour feet long and therefore extends along half the length of turbineportion 335. Each of these blades is also four feet long, but they arepositioned on the other half of turbine portion 335. Since the two setsof turbine blades are positioned on different halves of turbine portion335, the blades of the each set do not block the wind to the blades ofthe other set. Further, since the sets of blades are angularly offset(by 60 degrees in the figure,) the blades of one of the two sets will bemore optimally positioned to catch the wind and restart the spinning ofthe turbine after it stops. The blade sets may also line up evenly asopposed to offset positioning.

Support structure 336 also includes a cross-brace 337 which serves bothto stiffen the support structure and to provide a mounting point for agenerator. Pulleys are provided on the turbine portion 335 andgenerator, respectively. A belt couples the two pulleys so that whenturbine portion 335 (including the corresponding pulley) rotates, thisdrives the belt which in turn rotates the pulley on the generator,thereby driving the generator and causing it to generate electricity.Additional pulley and belt systems as well as a gearboxes may beintegrated into the turbine system. Structure 337 may also have acomponent to adjust the entire turbine's position and height—this wouldenable the turbine to maximize the wind's continual change in direction.

Also shown in FIG. 3 is a concentrator 350. Concentrator 350 is mountedon a concentrator support 351 which can be mounted to deflector 120 or aparapet if existing. Concentrator 350 is used to redirect andconcentrate the wind flow toward turbine portion 335. Concentrator 350is an optional component of the system which may be helpful to increasevortex wind flow circulating around the turbine axle. Alternatively,concentrator 350 may allow the wind flow to be redirected so thatturbine portion 335 can be positioned farther from the edge of the roof,making the installation of the system less obvious and moreaesthetically pleasing.

As depicted in FIG. 3, concentrator 350 is adjustable. A second positionof concentrator 350 is shown by the dotted lines in the figure. It maybe desirable to adjust to the position of concentrator 350 to optimizethe wind flow across turbine portion 335. Concentrator 350 may also beused to spoil the wind flow if the wind speed becomes too high. In otherwords, if the wind flow is sufficiently high that the turbine structuremay be damaged, concentrator 350 may be positioned to block, or spoil,the excess wind flow, using an automatic spring loaded pivoting system.The position of concentrator 350 may be manually or automaticallyadjustable. Another enhancement to concentrator 350 is the placement ofsolar cells 360 on the upper surface of the concentrator. Solar cellsmay augment the electricity generated by the turbine system, and mayeven provide the only source of electricity if the wind flow acrossturbine portion 335 is insufficient to drive the system.

Referring to FIG. 4, a diagram illustrating a reverse-wind-flowdeflector as used in one embodiment is shown. In this embodiment, windturbine structure 430 is again shown mounted at the edge of a building410. In this figure, however, the wind is depicted as flowing from rightto left. In other words, the wind is not blowing over the deflector 411at the edge of the building, but is instead coming across the rooftop.While the turbine portion of the wind turbine structure is designed torotate in the same direction (clockwise in the figure,) regardless ofthe direction from which the wind strikes it, a reverse-wind-flowdeflector 440 is positioned behind the wind turbine structure 430 and isoriented with surface 450 toward the turbine structure so that windhitting the deflector is directed to the lower half of the turbineportion. Deflector 440 thereby concentrates the wind on the lower half,where it can push the turbine blades, and reduces the wind hitting theupper half, where it would resist the (clockwise) rotation of theturbine blades.

The embodiment shown in FIG. 4 may include a side mounted concentratoror augmenter. In this case, the wind turbine structure is again mountedat the edge of a building as shown in the figure, with the wind flowingfrom the back of the embodiment. In other words, the wind is not blowingover the deflector at the edge of the building, but is instead comingacross the rooftop. While the turbine portion of the wind turbinestructure is designed to rotate in the same direction (clockwise in thefigure,) regardless of the direction from which the wind strikes it, aside mounted concentrator is positioned to the left or right of windturbine structure and is oriented so that wind hitting the deflector isdirected to the lower half of the turbine portion. The concentratorthereby concentrates the wind on the lower half, where it can push theturbine blades and reduce the wind hitting the upper half, where itwould resist the (clockwise) rotation of the turbine blades.

Referring to FIG. 5, a turbine system mounted concentrator or augmenter521 is shown in the 90-degree angle formed by the base of the turbineframe and the deflector. This device further concentrates the vortex toflow around the center of the turbine axle, as well as eliminating theair flow from eddying.

Referring to FIG. 6, a diagram showing the turbine system atop abuilding placed directly behind the parapet wall 612. The turbine systemmounted deflector 615 backs up directly to the parapet wall 612. Aconnector 611 connects the parapet wall to the turbine system mounteddeflector 615.

The foregoing description corresponds to an exemplary embodiment. It iscontemplated that many variations of the features described above, aswell as others which are not explicitly described, may be possible inalternative embodiments. Some of these variations will be describedbriefly below. These variations will be apparent to persons of ordinaryskill in the field of the invention upon reading the present disclosure,and are believed to be within the scope of the appended claims.

In the exemplary embodiment described above, the turbine structure isplaced near the edge of the building. The structure does not require aparapet wall but if one exists, deflector/concentrator/augmenter systemmay be mounted on the top of the parapet or the inside or outside edgeof the parapet wall or on the roof of the building behind the parapet.As noted above, the turbine structure can be mounted on the roof awayfrom the vertical face of the building to facilitate installation or toreduce the aesthetic impact of the installation. The wind will still beused to drive the turbine through proper placement of the system andthrough the use of a concentrator or augmenter. The position of theturbine structure can be adjusted by means of various types of mountingbrackets, the use of various mounting holes in the brackets, and so onto allow positioning that is optimal for the given site and prevailingconditions. The mounting brackets may include vibration-dampeningsupports to reduce the transmission of generated noise into thebuilding.

The structure may be built in modular sections (e.g., from 4 to 20 feetin width and from 2 to 8 feet in diameter.) This may aid installationand allow systems and/or components to be easily and economically massmanufactured, shipped and installed. The units can operate independently(e.g., each independently generates electricity) or, if desired, to saveequipment and maintenance costs, the units can be mechanically linkedtogether using a flexible drive shaft coupling. To link two adjacentturbines, a coupling is fastened where generator originally existed.Coupling links the two or more turbines and the generator or alternatormay be placed at either or both ends of the entire turbine assembly. Themechanical linkage between the units could provide a more economicalinstallation and could reduce the number of alternators/generators,wiring or similar equipment used to produce electricity. The number ofmodular sections, length or diameter of the turbine(s) can be customizedto utilize the full perimeter of a particular building if desired. Aspointed out above, the system can be installed on multiple sides of thebuilding to optimize the variations of the seasons and general winddirection. Each unit may be independently mounted on a swivel base 340such as an adjustable rotatable bearing or similar device to accommodatefor varying wind directions and conditions. The swivel base may beconstructed as, but is not limited to, a ball bearing sliding mechanism.A lever (or bearing switch or other mechanism) can be provided so that,when the lever is in an open position, the swivel base rotates atop theroof, turning into the direction the wind is strongest. When the leveris in a closed position, the position of the turbine system is locked,so that it does not swivel. (When the turbine system is locked, theorientation of the system is fixed, but the turbine blades are stillallowed to turn.) The lever may be manually locked or opened by hand, oran automatic locking/unlocking mechanism 341 may be provided.

The exemplary turbine structure described above uses a cylindricalturbine. The cylindrical design of the turbine and horizontalorientation of the turbine may be desirable to make the most efficientuse of the concentration of wind coming over the horizontal edge of theroof. It is not necessary, however, to use this type of turbine design,and other embodiments may use propeller-style or other types ofturbines, and the turbines may be oriented horizontally, vertically, orotherwise. The diameter, size or other design parameters of the turbinesmay vary, depending on such factors as the height of the building,strength or variability of the wind, typical weather conditions, theamount of energy required, and so on.

Some of the advantages of the various embodiments of the invention mayinclude its low cost, efficiency and maintainability in comparison toconventional windmills and vertical straight-wing-type turbines. Forexample, cylindrical-type turbines cannot be effectively employed inground installations due to the reduced speed of wind next to the groundWhen cylindrical-type turbines are deployed vertically (standing up,)they exert tremendous unbalanced forces on their axle bearings. Thepresent system allows the use of cylindrical-type turbines with theiraxis of rotation parallel to the ground, reducing the stress on thebearings and allowing inexpensive long-life bearings to be employed.Conventional vertical installations also typically require the use ofguy wires that anchor the turbine to the ground, increasing the forceson the bearings, and increasing the complexity of the installation. Thepresent system reduces the stress the system and the complexity andexpense of the installation. Compared to conventional methods, thepresent system may reduce the stress caused by vibration from the wind,which in turn reduces the maintenance/expense and the complexity of theinstallation. The present system is also more efficient and quiet thantypical conventional turbine systems because of the use of deflectorsand vortex created by building updraft to drag the wings around thecomplete rotation of the axle while the flow of wind against the portionof the turbine that is moving in the direction opposite the wind flow.

When wind blows against the face of a building, the air in contact withthe building face is compressed by the force of the moving air behindit. This force, combined with the reflected force from the inertia ofthe impacting air, causes the air at the building face to move around toeither the sides of the building or over the top of the building. Evenallowing for increased friction flow resistance against the buildingwall and at the edge of the roof deflector, the air moving over the edgeof the deflector is greatly accelerated over the speed of the ambientair (the speed of the wind in the absence of the vertical surfaces ofthe building or other structure).

Because the wind turbine of the present system is positioned at the edgeof the roof, this vortex of high-energy moving air drives the turbine,extracting the wind's energy and generating electricity. Although it maybe omitted or given a variety of shapes, the concentrator (also called abaffle or augmenter) is used in the preferred embodiment to funnelmoving air into the wind turbine. The adjustable concentrator allows thedevice to compensate for placement issues that may make it difficult toplace the wind turbine at the point of greatest air flow. The device,its mounts and the concentrators, augmenters and deflectors areconfigured to provide the most advantageous airflow to the wind turbine.The concentrator, extending past the building edge 410, concentrates theupdraft airflow contour near the edge of the building, directing airflow into rotational vortex pattern, to prevent moving air from passingup and high over the building, beyond the reach of the wind turbine'sblades.

As noted above, the concentrator and deflectors may includesolar-electric panels on their upper surface in order to generateelectricity independently or in conjunction with turbine mechanism. Theconcentrator may further include mechanical actuators to adjust theposition of the concentrator and to thereby improve both thewind-gathering ability and the light-gathering ability of theconcentrator.

Alternative embodiments may also include turbine blades that aredesigned to break in very high winds in order to prevent more extensiveand more expensive damage to the turbine. For instance, in oneembodiment, the turbine blades may be made from a sail material thattears away from a blade frame to protect the structure from destructivewinds. The sail material may be attached to the frame by hook-and-loopmaterial 338 (e.g., “velcro”) so that the attachment to the frame fails,or it may be sewn together so that the sail material itself tears. Thismechanism may be implemented using the concentrator, and or a separatespoiler(s) which are positioned along the length of the turbine. Whendestructive operation is detected (electrically or mechanically) anactuator is activated or a catch is released (electrically ormechanically,) allowing the spoiler to block airflow to the turbine.

In the preferred embodiment, each section contains its own electricalgenerating mechanism and electronic power management circuitry. In someembodiments, some sections may not have independent electrical powergenerating capability. They may instead be mechanically coupled to othersections to provide additional mechanical power to another section thathas electricity generating equipment. Other segments may incorporate awater pump instead of an electrical generator, to help pump waterthrough the building, or a fresh air system to reduce HVAC costs andforce fresh air into the building when the temperatures are correct. Inanother embodiment a linkage to a ventilator system that will augmentelectrically-powered air handling systems when the wind is blowing. Themechanical power of the turbines may be harnessed for other purposes aswell.

The benefits and advantages which may be provided by the presentinvention have been described above with regard to specific embodiments.These benefits and advantages, and any elements or limitations that maycause them to occur or to become more pronounced are not to be construedas critical, required, or essential features of any or all of theclaims. As used herein, the terms “comprises,” “comprising,” or anyother variations thereof, are intended to be interpreted asnon-exclusively including the elements or limitations which follow thoseterms. Accordingly, a system, method, or other embodiment that comprisesa set of elements is not limited to only those elements, and may includeother elements not expressly listed or inherent to the claimedembodiment.

While the present invention has been described with reference toparticular embodiments, it should be understood that the embodiments areillustrative and that the scope of the invention is not limited to theseembodiments. Many variations, modifications, additions and improvementsto the embodiments described above are possible. It is contemplated thatthese variations, modifications, additions and improvements fall withinthe scope of the invention as detailed within the following claims.

1. A system comprising: a wind turbine; and a deflector surface; whereinthe wind turbine is mounted on a roof of a building near an edge of theroof and positioned to enable the wind turbine to be driven by wind flowwhich is passively concentrated by a vertical face of the building andflows up and over the edge of the roof; wherein the wind turbine ispositioned within a vortex created by the concentrated wind flow overthe edge of the roof; wherein the deflector surface is positioned on aside of the turbine facing substantially away from the edge of the roofand wherein the deflector surface directs wind downward on the side ofthe turbine facing substantially away from the edge of the roof, therebyconcentrating the wind flow of the vortex.
 2. The system of claim 1,further comprising a concentrator mounted near the edge of the roof andconfigured to further concentrate the wind flow over the edge of theroof.
 3. The system of claim 2, wherein the concentrator is mounted to aparapet wall at the edge of the roof.
 4. The system of claim 3, whereinthe parapet wall screens a counter-rotating portion of the wind turbinefrom the concentrated wind flow while allowing the concentrated windflow to reach a portion of the wind turbine that rotates with theconcentrated wind flow.
 5. The system of claim 1, wherein the windturbine comprises a cylindrical turbine structure having an axis aboutwhich a plurality of turbine blades rotate, and wherein the wind turbineis oriented with the axis parallel to the edge of the roof.
 6. Thesystem of claim 1, wherein the wind turbine comprises a plurality ofturbine blades and wherein the turbine blades are configured to fail inhigh-wind-flow conditions and thereby prevent damage to the remainder ofthe turbine.
 7. The system of claim 6, wherein the turbine bladescomprise frames covered with a sail material.
 8. The system of claim 7,wherein the sail material is attached to the turbine blade frames usinghook-and-loop closure material.
 9. The system of claim 7, wherein thesail material is configured to tear away from the turbine blade framesin high-wind-flow conditions.
 10. The system of claim 1, furthercomprising a swivel base upon which the wind turbine is mounted.
 11. Thesystem of claim 10, further comprising a locking mechanism configured tolock the swivel base in a fixed position when the locking mechanism isengaged.
 12. A method comprising: providing a cylindrical wind turbinehaving an axis about which a plurality of turbine blades rotate;mounting the wind turbine on a roof of a building; positioning the windturbine within a vortex created by the concentrated wind flow over anedge of the roof; and positioning a deflector surface on a side of thewind turbine facing substantially away from the edge of the roof,wherein the deflector surface directs wind downward on the side of theturbine facing substantially away from the edge of the roof, therebyconcentrating the wind flow of the vortex.
 13. The method of claim 12,wherein providing the cylindrical wind turbine comprises providing awind turbine that includes a plurality of turbine blades which areconfigured to fail in high-wind-flow conditions.
 14. The method of claim13, wherein the turbine blades comprise frames covered with a sailmaterial.
 15. The method of claim 14, wherein the sail material isattached to the turbine blade frames using hook-and-loop closurematerial.
 16. The method of claim 14, wherein the sail material isconfigured to tear away from the turbine blade frames in high-wind-flowconditions.
 17. A system comprising: a wind turbine, wherein the windturbine is mounted on a roof of a building near an edge of the roof andpositioned to enable the wind turbine to be driven by wind flow which ispassively concentrated by a vertical face of the building and flows upand over the edge of the roof, and wherein the wind turbine ispositioned within a vortex created by the concentrated wind flow overthe edge of the roof; a vortex deflector surface, wherein the vortexdeflector surface is positioned to concentrate the wind flow of thevortex on a portion of the turbine facing substantially away from theedge of the roof; and a concentrator mounted to a parapet wall at theedge of the roof and configured to further concentrate the wind flowover the edge of the roof.